1. Field of the Invention
The present invention relates to method of processing fermented liquid derived from plants such as cornstarch, wheatstarch or the like and a processor therefor. The word "fermented liquid" means a liquid, derived mainly from plant, in which fermentation has taken place artificially and/or naturally.
2. Description of the Prior Art
Fermented liquid as a waste product from cornstarch or wheatstarch factories contains a variety of volatile organic substances resulting in an extreme increase in chemical oxygen demand (referred to as COD). Thus, the fermented liquid may not be discharged without waste liquid treatment.
Waste liquid from cornstarch factories is usually subjected to a vacuum condensation treatment by means of a condenser, shown in FIG. 1, comprising four distilling tanks 100-103 in sequence and a cooler 104. The condensate fractions (a), (b), (c) and (d) discharged from the condenser are treated with an activated sludge method and then discharged into rivers. The COD of each condensate (a)-(d) is so high that these condensates make the load too heavy for use with the activated sludge used as a post-treatment. Thus, the application of the activated sludge method to those condensates is troublesome and/or costly. Moreover, useful substances such as alcohol contained in the fermented liquid are discharged without recovery.
Likewise, waste liquid from wheatstarch factories is condensed by means of the condenser shown in FIG. 1. The resulting condensates (a), (b) and (c) are combined and supplied to a distilling column, the bottom residue from which is combined with the remaining condensate (d) and subjected to an activated sludge method. This processing of the wheatstarch waste liquid requires large scale equipment and a large amount of heated vapor. The COD of the waste liquid to be applied to the activated sludge is also so high that a heavy load is imposed on the sludge thereby making the processing troublesome and costly as in the abovementioned cornstarch waste liquid.